The U.S. government ran a $53.2 billion surplus in December, signaling further improvement in the nation's finances.

The surplus was the largest since September and a record for the month of December. It was boosted by nearly $40 billion in payments from mortgage giants Fannie Mae and Freddie Mac.

For the first three months of the budget year, which began on Oct. 1, the Treasury has run a deficit of $173.6 billion. That's 40.8 percent below the $293.3 billion deficit run during the same period last year.

An improving economy and higher tax revenues trimmed the 2013 deficit to $680 billion. That followed four consecutive years of $1 trillion-plus deficits.

Rising tax revenues and government spending constraints are expected to trim this year's deficit to around $600 billion.